How long is a piece of string. At our agency we have spent over 30 hours on our research for certain ecommerce clients. I would say the average is 5-10 hours. The SEO landscape is shifting though however. Keywords with volume are not the only game in town and in reality are a zero sum game. The keywords with volume are the most competitive and if you manage to outrank a competitor they are not going to just watch you zoom past them and do nothing.
At Vine Digital we focus on delivering more sales, more leads or whatever other business metric is key to the client. Old school keyword research is becoming less valuable now that everyone with an ahrefs & semrush account can do it
ZSV Keywords (Zero Search Volume)
This topic is trending in SEO at the moment and with good reason. With the arrival of Google’s most recent major algorithm updates(BERT especially) the search engines ability to answer exact queries has improved dramatically and as such the amount of long tail keyword opportunities has exploded, and the vast majority of these will have no search volume.